Modes of Cannabis Use and Mental Health Outcomes Among Older Adults in the United States.

BACKGROUND: Cannabis use among older adults (≥ 65) in the US has increased substantially in recent years. However, physiologic changes associated with aging can complicate cannabis' effects in older populations, particularly as different modes of consumption have distinct pharmacokinetic effects. This study estimates the prevalence of different modes of cannabis use in this population and examines their associations with mental health outcomes. METHODS: We analyzed data from older adults aged ≥ 65 years with past-year cannabis use (N = 1515) from the pooled 2022-2024 National Survey on Drug Use and Health, a nationally representative survey of noninstitutionalized US adults. Four generalized linear models using Poisson and log link examined relationships between modes of cannabis use and cannabis use disorder (CUD), major depressive episode (MDE), serious psychological distress (SPD), and suicidal ideation (SI). The modes examined included smoking, ingested forms (eating/drinking or taking pills), inhaled concentrates (vaping or dabbing), and other routes (use of oral drops/lozenges or topicals). The models adjusted for survey year, sociodemographic characteristics, past-year cannabis use frequency, and other past-year substance use. RESULTS: Smoking (66.0%) was the most common mode of cannabis use, followed by ingested forms (42.1%), inhaled concentrates (17.1%), and other routes (16.8%). Compared to males, females had higher prevalence of ingested forms and other routes, while males had higher prevalence of smoking and inhaled concentrates. In multivariable models, smoking (adjusted prevalence ratio [aPR] = 3.99; 95% CI: 1.92-8.28) and ingested forms (aPR = 1.46; 95% CI: 1.03-2.09) were associated with increased prevalence of CUD. No mode was associated with MDE, SPD, or SI. CONCLUSIONS: Among older adults, smoking and ingested forms were associated with CUD, whereas no mode was associated with depression, distress, or suicidal ideation. These findings may inform targeted screening and harm reduction strategies for adults aged ≥ 65 years using cannabis.